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    <meta charset="UTF-8"/>
    <title>何为数据代理</title>
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<!-- 数据代理：通过一个对象代理对另一个对象中属性的操作（读/写）-->
<script type="text/javascript">
    let obj = {x: 100}
    let obj2 = {y: 200}

    Object.defineProperty(obj2, 'x', {
        get() {
            return obj.x
        },
        set(value) {
            obj.x = value
        }
    })
</script>
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